Supervisory apparatus



July 21, 1970 s, JEWlTT ET AL 3,521,281

SUPERVISORY APPARATUS Filed NOV. 13, 1968 2 Sheets-Sheet 1 52 M OD ULATOR STATION AND RANGE REPLY GEN.

TILT

ALARM 24 S IGNAL GEN.

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GENERATOR m To i 74 SELECTOR TILT SWITCH so 92 75 sa H Q 7| 36 W lol 8 NC. 403 I02 77 13' loo r I04 I05 80 INVENTORS HAROLD S. JEWITT DELBERT E. MARKER ATTORNEY July 21, 1970 s, JEWITT ET AL 3,521,281

SUPERVISORY APPARATUS Filed Nov. 13, 1968 2 Sheets-Sheet 2 TILT I l RECEIV- I PULSE ANGLE ER DET. DECODER |2o L 5 *ISO FIG. 3

FROM PULSE DETECTOR '5' LAY 7 GEN. T I56 FROM DELAY LINE 2 FIG. 4

TO TILT LAMP INVENTORS HAROLD S. JEWITT DELBERT E MARKER ATTORNEY United States Patent U.S. Cl. 343-68 11 Claims ABSTRACT OF THE DISCLOSURE Apparatus for interrupting the transmission of radio signals from a radiator, if the radiator becomes physically displaced from a predetermined angular orientation. The radiator includes an omnidirectional antenna, energized alternately with an array of directional antennas defining a path in space. Tilt responsive switch means is provided to prevent radiation from the directional antennas, while not aifecting the radiation from the omnidirectional antenna, but in fact adding thereto a further signal indicative of a tilt situation.

CROSS-REFERENCE The invention here comprises an improvement on the landing system which is the subject matter of copending Leyde application 574,225, filed Aug. 22, 1966 and assigned to the assignee of the present application.

BACKGROUND OF THE INVENTION This invention relates to the field of supervisory apparatus, and more particularly to apparatus for use in controlling the movements of one or more aircraft to follow a predetermined path in space. It is customary to do this by means of directional antennas properly located and oriented with respect to one another to make up a directional array. A convenient arrangement is one in which a first pair of antennas provide signals which cooperate to define the path in elevation, and a second pair of antennas provide signals which cooperate to define the path in azimuth. The signals may be jointly referred to as guidance signals. It is at once apparent that if the antenna assembly is physically displaced angularly by some accident or inadvertence, the path thereafter by defined by the antennas is no longer that desired, and may indeed be dangerous because it is now too steep or too close to a hazard such as a tall structure adjacent the landing area.

The co-pending application referred to above discloses apparatus, including the directional antennas, for providing the desired path. It also shows a further omnidirectional antenna, physically associated with the directional antennas, for transmitting a further signal, unrelated to the guidance signals. Naturally, any tilt of the antenna assembly will not be of significance as regards the omnidirectional signal, which is essentially the same in all directions.

SUMMARY OF THE INVENTION The present invention adds to the known ground equipment means for detecting tilt of the antenna assembly and means actuated thereby for preventing any radiation from the directional antennas, while at the same time adding to the omnidirectionally radiated signal, a signal indicating tilt of the antenna. In the airborne equipment, the added signal actuates a Warning lamp, indicating that any directional indications are not to be relied on.

Various objects, advantages, and features of novelty which characterize our invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and objects attained by its use, reference should be had to the drawing which forms a further part hereof, and to the accompanying descriptive matter, in which we have illustrated and described a preferred embodiment of our invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing, FIG. 1 shows the ground-based portion of a system incorporating the invention, in block diagram, FIG. 2 gives details of the tilt alarm of FIG. 1, FIG. 3 shows the airborne portion of a system incorporating the invention in block diagram, and FIG. 4 gives details of the tilt alarm.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, the ground based portion of a system embodying our invention is shown in block diagram to comprise as major elements a signal generator 10, a receiver 11 including an omnidirection receiving antenna 12, a station code and range reply generator 13, a modulator 14, a tilt alarm 15, a lobe selector 16, a transmitter 17, a two-position RF switch 20, a four-position RF switch 21, an omnidirectional transmitting antenna 22, and Up, Down, Left, and Right directional antennas 23, 24, 25 and 26.

Generator 10 is connected to generator 13 by conductor 27, and to tilt alarm by conductors 30 and 31. Tilt alarm 15 is connected to switch by conductors 32 and 33. Generator 13 is connected to modulator 14 by conductors 34, 35, 36 and 37, and to tilt alarm 15 by conductor 40. Tilt alarm 15 is connected to lobe selector 16 by conductor 41, and to modulator 14 by conductor 42. Lobe selector 16 is connected to modulator 16 by conductor 43 and to switch 21 by conductors 44, 45, 46 and 47. Modulator 14 is connected to transmitter 17 by conductor 50, transmitter 17 is connected to switch 20 by conductor 51, and switch 20 is connected to switch 21 by conductor 52. Antenna 22 is connected to switch 20, and antennas 23, 24, 25 and 26 are connected to switch 21. Receiver 11 is connected to generator 13 by conductor 53.

FIG. 2 shows tilt alarm 15 to comprise a source of voltage positive with respect to ground 61, a source 62 of voltage negative with respect to ground, a tilt switch 63 including fixed contact means 64 and pendously movable contact means 65, a first relay 66 including a winding 67 which energizes an armature 70 to actuate a pair of movable contacts 71 and 72 out of normal engagement with fixed contacts 73 and 74 and into engagement with fixed contacts 75 and 76, all respectively, a second relay 77 including a winding 80 which energizes an armature 81 to actuate a pair of movable contacts 82 and 83 out of normal engagement with fixed contacts 84 and 85 and into engagement with fixed contacts 86 and 87, a reset switch 89 and a delay generator Conductor 40 is connected to movable contact 72, conductor 41 is connected to fixed contact 74, and conductor 42 is connected to generator 90. Conductors 30 and 31 are connected to fixed contacts 84 and 85 and movable contacts 82 and 83 are connected to conductors 32 and 33. Positive source 60 is connected to movable contact 65 through switch 89 and conductor 91, to fixed contact 75 through switch 89 and conductor 92, and to fixed contact 87 through switch 89 and conductor 93. Negative source 62 is connected to fixed contact 86 through conductor 94. Fixed contact 76 is connected to delay generator 90 by conductor 95. Fixed contact 64 is connected to one end of winding 67 through a path made up of conductors 96, 97 and 100; the other end of winding 67 is grounded. Fixed contact 64 is also connected to one end of winding 80 through a path made up of conductors 96, 101 and 102; the other end of winding 80 is grounded. Fixed contact 64 is also connected to movable contact 71 through a path made up of conductors 96, 97, and 103. Transient suppression diodes 104 and 105 are connected across wind ings 67 and 80 respectively.

In the normal condition of tilt alarm 15 pendulous contact 65 is at a central dead spot on fixed contact 64 and relays 66 and 77 are de-energized. Conductors 30, 31 and 40 are connected to conductors 32, 33 and 41 respectively.

In FIG. 1, generator supplies a signal to generator 13 through conductor 27, and one to switch 20, through conductor 30, tilt alarm 15 and conductor 32. The latter signal acts through switch to connect conductor 51 to conductor 52 rather than to antenna 22. The former sig nal triggers generator 13 to supply three successive pulses to modulator 14, on conductors 35, 36 and 37 respectively, which are delayed by predetermined intervals after the pulse from generator 10 according to a time code which identifies the transmitting station. Generator 13 supplies a pulse through conductor 40, tilt alarm 15 and conductor 41 to lobe selector 16, which supplies a further delayed guidance pulse to modulator 14 through conductor 43 and also supplies a signal on one of connections 44, 45, 46 and 47 to actuate switch 21 so that a selected one of antennas 23, 24, and 26 is connected to conductor 52. Modulator 14 acts through conductor 50 to modulate transmitter 17 with the station code and guidance pulses, and the transmitter supplies a train of four bursts of RF energy through conductor 51, switch 20, conductor 52, and switch 21 to the selected antenna.

The above requires only a small part of the period of generator 10, which presently reverts to its initial state, interrupting the signal on conductors and 32 and substituting a signal on conductors 31 and 33 which acts in switch 20 to connect conductor 51 to antenna 22 instead of to conductor 52, thus disabling antennas 23, 24, 25 and 26. Now if a pulse is received on antenna 12 it acts through receiver 11 and conductor 53 to trigger generator 13, which then supplies a reply pulse to modulator 14 on conductor 34, and this results, through conductor transmitter 17, conductor 51, and switch 20, in the radiation of a reply pulse from antenna 22.

Details and refinements of the general system form no part of the present invention and are not shown in the drawing.

Now if the antenna assembly is tilted so that movable contact 65, FIG. 2, engages fixed contact 64, relays 66 and 77 are energized, and movable contact 71 engages fixed contact 75 to complete a holding circuit for the relays, thus maintaining the new condition of the system until reset switch 89 is operated. Movable contact 72 disengages fixed contact 74, disabling the lobe selector, and engages fixed contact 76, so that each pulse on conductor 40 results in a delayed tilt alarm pulse at conductor 42 instead of a guidance pulse at conductor 42. Movable contacts 82 and 83 disengage fixed contacts 84 and 85 and engage fixed contacts 86 and 87 instead, thus connecting conductors 32 and 33 to sources 62- and 60, all respectively. This results in permanent energization of switch 20 so that antenna 22 is continuously connected to conductor 51. Each pulse of generator 10 now results in transmitter operation to give a set of station code pulses followed by a tilt alarm pulse, and the four pulses are now radiated from antenna 22 rather than from any guidance antenna.

Turning now to FIG. 3 of the drawing, the airborne portion of this system is shown to comprise a receiver having an omnidirectional antenna 121, a station decoder 122 including a pulse detector 123, a first delay line 124, a first AND circuit 125, a second delay line 126, and a second AND circuit 127, an angle decoder 128, a gating arrangement 130, an indicator assembly 131 including azimuth and elevation cross-pointers and warning flags, a tilt alarm 132 and a warning light 133.

Receiver 120 is connected to pulse detector 123 by conductors 140 and 141 and to gating arrangement by conductors and 142. Detector 123 is connected to delay line 124 by conductors 143 and 144, to AND circuit 125 by conductors 143, 145, 146 and 147, to AND circuit 127 by conductors 143, 145, 146 and and to tilt alarm 132 and by conductros 143, 145, and 151. Delay line 124 is connected to AND circuit 125 by conductor 152, and AND circuit 125 is connected to delay line 126 by conductor 153. Delay line 126 is connected to AND circuit 127 by conductors 154 and 155, and to tilt alarm 132 by conductors 154 and 156. AND circuit 127 is connected to decoder 128 by conductor 157. Gating assembly 130 is connected to detector 123 by conductor 158 and to decoder 128 by conductor 159. Decoder 128 is connected to gating assembly 130 by conductor 160, and gating assembly 130 is connected to indicator assembly 131 by conductors 161, 162, 163 and 164. Tilt alarm 132 is connected to lamp 133 by conductor 165.

The range interrogation components of the airborne part of the system have no bearing on the present invention and are not shown in the drawing; the same is true for the range response reception and presentation components.

The tilt alarm circuitry is shown in more detail in FIG. 4 to comprise a delay circuit 171, a gate generator 172, an inverter 173, a second AND circuit 174, a driver 175, an amplifier 176, a source 177 of voltage positive with respect to ground 180, a relay 181 having a winding 182 which energizes an armature 183 to actuate a movable contact 184 out of normal engagement with a first fixed contact 185 and into engagement with a second fixed contact 186, and a transient suppressing diode 187.

Conductor 156 from delay line 126 is connected to delay 171, which is connected through conductor 190, delay 171, conductor 191, gate generator 172, conductor 192, inverter 173, and conductor 193 to AND circuit 174. Conductor 151 from pulse detector 123 is also connected to AND circuit 174, which is in turn connected through conductor 194, driver 175, conductor 195, amplifier 176 and conductor 196 to relay 181.

In normal operation of the system, the four-pulse train radiated by one of antennas 2326, FIG. 1, appears at antenna 121, FIG. 3, and results in a train of input pulses to station decoder 122, enabled through conductor 158 by gating assembly 130. Delay lines 124 and 126 are adjusted to agree with the time coding of the first three pulses from the fixed station, and when a pulse train matching the delay line coding is received a signal is passed to angle decoder 128. Decoder 128 is enabled by gating arrangement 130 through conductor 159, to keep the airborne equipment synchronized with fixed station equipment, by means forming no part of the present invention, the circuitry being disclosed in the co-pending application referred to. The gating arrangement also accepts the output of decoder 128 on conductor 160 and supplies it to the proper cross-pointer meter in indicator 131 through conductors 161 and 162 or conductors 163 and 164. As long as signals are being supplied on these four conductors the warning flags on the cross-pointer meters are withdrawn.

By reason of delay 171, the input to AND circuit 174, FIG. 4, on conductor 193, is not simultaneous with that on conductor 151, and relay 181 remains unenergized.

If now the fixed station antenna assembly is displaced so that the tilt alarm switch is operated, antenna 121 of FIG. 3 receives no angle pulses. No inputs are supplied on conductors 161-164, the cross-pointers return to their central zero positions, and the warning flags appear. Since this may take some time, an immediate signal is supplied to warn the pilot. The tilt alarm pulses which have replaced the angle pulses are so timed, with respect to delay 171, FIG. 4, that simultaneous signals now reach AND circuit 174 on conductors 151 and 193, and relay 184 is energized to light warning lamp 133.

Numerous objects and advantages of our invention have been set forth in the foregoing description, together with details of the structure and function of the invention, and the novel features thereof are pointed out in the appended claims. The disclosure, however, is illustrative only, and we may make changes in detail, especially in matters of shape, size and arrangement of parts, within the principle of the invention, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

We claim as our invention:

1. In combination:

means, including radiating means, for transmitting a first signal;

means carried by said radiating means and responsive to displacement thereof from a predetermined orientation;

and means actuated by the response of said last named means for interrupting the transmission of said first signal and initiating transmission of a second signal. 2. In combination: means providing a first radio signal; means directionally radiating said first signal; means responsive to the displacement of the radiating means from a predetermined orientation; and

means actuated by the response of the last named means for interrupting the directional radiation of said first signal and initiating omnidirectional radiation of a second radio signal distinguishable from said first signal.

3. In combination:

means providing a first train of pulses;

means directionally radiating said pulses to define a path in space; means responsive to the displacement of the radiating means from a predetermined orientation; and

means actuated by the response of the last named means for interrrupting the directional radiation of pulses and initiating omnidirectional radiation of a second train of pulses distinguishable from the pulses of said first train.

4. Apparatus according to claim 2 together with remote means for receiving said signals, means for performing a first function in accordance with the first signal, and means for performing a second function in accordance with the second signal.

5. Apparatus according to claim 2 in which the directionally radiating means comprlses an array of antennas.

6. Apparatus according to claim 2 in which the directionally radiating means comprises an array of dipole antennas.

7. Apparatus according to claim 2 in which the displacement responsive means comprises a tilt switch.

8. Apparatus according to claim 2 together with means for continually providing a further signal in response to a received interrogation, regardless of the operation of the interrupting means.

9. Apparatus according to claim 3 together with remote means for receiving said trains of pulses, first supervisory means responsive to the pulses of said first train for indicating displacement of the remote means from the path in space and second supervisory means actuated in accordance with the pulses of said second train.

10. In combination:

means for supplying a train of high frequency pulses;

means for supply further high frequency pulses in reply to interrogation pulses;

an omnidirectional radiator;

an assembly of directional radiators;

switch means supplying the pulses of said train to the radiators of said assembly in a predetermined sequence, and supplying the reply pulses to said omnidirectional radiator; and

means responsive to tilt of said assembly for preventing said switch means for supplying pulses to said assembly.

11. Apparatus according to claim 10 in which the last named means further includes a means of supplying a further train of high frequency pulses to said omnidirectional radiator.

References Cited UNITED STATES PATENTS 2,412,703 12/1946 Wolfi 343-876 X 3,095,538 6/1963 Silberstein 343-876 X 3,230,348 1/1966 Hammond 244-313 X 3,336,591 8/1967 Michnik et al.

RICHA RD A. FARLEY, Primary Examiner M. F. HUBLER, Assistant Examiner U.S. c1. X.R. 

